Light emitting diode having an adhesive layer and a manufacturing method thereof

ABSTRACT

A method for forming a light emitting diode includes forming a first stack, forming a second reaction layer over the first stack, forming a second stack, forming a first reaction layer over the second stack, and holding together the first reaction layer and the second reaction layer by means of a transparent adhesive layer. The transparent adhesive layer is formed between the first and second reaction layer, therefore the second reaction layer of the first stack will not come off the first reaction layer of the second stack.

BACKGROUND OF INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a light emitting diode, and moreparticularly, a light emitting diode having an adhesive layer tostrengthen the structure of the light emitting diode.

[0003] 2. Description of the Prior Art

[0004] Light emitting diodes are widely used in optical displays, laserdiodes, traffic lights, data storage devices, communications devices,illumination equipments, and medical equipments. Therefore, enhancingthe performance of the light emitting diodes is an important issue inthe field of LEDs.

[0005] Related art teaches a light emitting diode and its manufacturingmethod in which the light emitting diode is formed by adhering atransparent insulating adhesive layer to an emitting stack and atransparent substrate. The adherence is achieved by Van der Waalsforces. However the Van der Waals forces are too weak to hold theemitting stack and the transparent substrate in place. Therefore theemitting stack may come off the transparent substrate easily.

SUMMARY OF INVENTION

[0006] It is therefore an object of the claimed invention to develop alight emitting diode with a strong structure to solve the aforementionedproblem.

[0007] According to the first claimed invention, the method for forminga light emitting diode comprises forming a first stack, forming a secondstack, forming a second reaction layer over said first stack, forming afirst reaction layer over said second stack, and holding together saidfirst reaction layer and said second reaction layer by means of atransparent adhesive layer.

[0008] According to the second claimed invention, the light emittingdiode comprises a first stack, a second reaction layer formed on thefirst stack, a second stack, a first reaction layer formed on the secondstack, a transparent adhesive layer formed between the first and secondreaction layers, and first and second electrodes formed on the firststack.

[0009] These and other objects of the claimed invention will no doubtbecome obvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0010]FIG. 1 is a perspective view of a light emitting diode accordingto the present invention.

[0011]FIG. 2 is a perspective view of a first stack according to thepresent invention.

[0012]FIG. 3 is a perspective view of a second stack according to thepresent invention.

[0013]FIG. 4 is a perspective view of a third stack according to thepresent invention.

[0014]FIG. 5 is a perspective view of a fourth stack according to thepresent invention.

DETAILED DESCRIPTION

[0015] Please refer to FIG. 1. FIG. 1 is a perspective view of a lightemitting diode 1 according to the present invention. The light emittingdiode 1 comprises a second substrate 10, a first reaction layer 11formed on the second substrate 10, a transparent adhesive layer 12formed on the first reaction layer 11, a second reaction layer 22 formedon the transparent adhesive layer 12, and a transparent conductive layer21 formed on the second reaction layer 22. The transparent conductivelayer 21 has a first surface area and a second surface area. The lightemitting diode 1 further comprises a first contact layer 13 formed onthe first surface area of the transparent conductive layer 21, a firstcladding layer 14 formed on the first contact layer 13, an emittinglayer 15 formed on the first cladding layer 14, a second cladding layer16 formed on the emitting layer 15, a second contact layer 17 formed onthe second cladding layer 16, a first electrode 19 formed on the secondcontact layer 17 and a second electrode 20 formed on the second surfacearea of the transparent conductive layer 21.

[0016] Please refer to FIG. 2. FIG. 2 is a perspective view of a firststack 2 and the second reaction layer 22 according to the presentinvention. The first stack 2 and the second reaction layer 22 are formedin the following sequence: forming a first substrate 18, forming thesecond contact layer 17 on the first substrate 18, forming the secondcladding layer 16 on the second contact layer 17, forming the emittinglayer 15 on the second cladding layer 16, forming the first claddinglayer 14 on the emitting layer 15, forming the first contact layer 13 onthe first cladding layer 14, forming the transparent conductive layer 21on the first contact layer 13, and forming the second reaction layer 22on the transparent conductive layer 21.

[0017] Please refer to FIGS. 3 to 5. FIG. 3 is a perspective view of asecond stack 3 and the first reaction layer 11 according to the presentinvention. FIG. 4 is a perspective view of a third stack 4 according tothe present invention. FIG. 5 is a perspective view of a fourth stack 5according to the present invention. The second stack 3 and the firstreaction layer 11 are formed by forming the second substrate 10, andforming the first reaction layer 11 on the second substrate 10. Thethird stack 4 is formed by performing a chemical reaction to generate ahydrogen bond or an ionic bond between the second reaction layer 22 ofthe first stack 2 and the transparent adhesive layer 12, and to generatea hydrogen bond or an ionic bond between the first reaction layer 11 ofthe second stack 3 and the transparent adhesive layer 12. The chemicalreaction is performed with an increased temperature and may additionallywith an increased pressure. The fourth stack 5 is formed by removing thefirst substrate 18. After the fourth stack 5 is formed, the fourth stack5 is etched to the second surface area of the transparent conductivelayer 21. Then the first electrode 19 is formed on the second contactlayer 17, and the second electrode 20 is formed on the second surfacearea of the transparent conductive layer 21 to form the light emittingdiode 1.

[0018] The first substrate 18 comprises at least one material selectedfrom a group consisting of GaP, GaAs, Ge, and the like materials. Thesecond substrate 10 comprises at least one material selected from agroup consisting of SiC, Al₂O₃, glass materials, quartz, GaP, GaAsP,AlGaAs, and the like materials. The transparent adhesive layer 12comprises at least one material selected from a group consisting of Pi,BCB, PFCB, and the like materials. The first reaction layer 11 and thesecond reaction layer 22 each comprise at least one material selectedfrom a group consisting of SiNx, Ti, Cr, and the like materials. Thefirst contact layer 13 and the second contact layer 17 each comprise atleast one material selected from a group consisting of GaP, GaAs, GaAsP,InGaP, AlGaInP, AlGaAs, and the like materials. The first cladding layer14, the emitting layer 15, and the second cladding layer 16 eachcomprise AlGaInP or the like materials. The transparent conductive layer21 comprises at least one material selected from a group consisting ofindium tin oxide, cadmium tin oxide, antimony tin oxide, zincoxide, zinctin oxide, BeAu, GeAu, Ni/Au, and the like materials.

[0019] Compared with related art, a chemical reaction is performed togenerate a hydrogen bond or an ionic bond between the second reactionlayer 22 and the transparent adhesive layer 12, and to generate ahydrogen bond or an ionic bond between the first reaction layer 11 andthe transparent adhesive layer 12. The hydrogen bonds or ionic bonds canfirmly hold the second reaction layer 22 above the first reaction layer11. Therefore the second reaction layer 22 will not come off the firstreaction layer 11. The light emitting diode 1 has a strong structure.

[0020] Those skilled in the art will readily observe that numerousmodifications and alterations of the light emitting diode may be madewhile retaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

We claim:
 1. A method for forming a light emitting diode comprisingfollowing steps: forming a first stack; forming a second reaction layerover said first stack; forming a second stack; forming a first reactionlayer over saidsecond stack; holding together said first reaction layerand said second reaction layer by means of a transparent adhesive layer.2. The method of claim 1 wherein the step of forming a first stackcomprises following steps: providing a first substrate; forming a secondcontact layer on the first substrate; forming a second cladding layer onthe second contact layer; forming an emitting layer on the secondcladding layer; forming a first cladding layer on the emitting layer;forming a first contact layer on the first cladding layer; and forming atransparent conductive layer on the first contact layer.
 3. The methodof claim 2 further comprising following steps: removing the firstsubstrate; etching the second contact layer, the second cladding layer,the emitting layer, first cladding layer, and the first contact layer;and forming a first electrode on the second contact layer, and a secondelectrode on the transparent conductive layer.
 4. The method of claim 2wherein the first substrate comprises at least one material selectedfrom a group consisting of GaP, GaAs, and Ge.
 5. The method of claim 2wherein the first contact layer and the second contact layer eachcomprise at least one material selected from a group consisting of GaP,GaAs, GaAsP, InGaP, AlGaInP, and AlGaAs.
 6. The method of claim 2wherein the first cladding layer, the emitting layer, and the secondcladding layer each comprise AlGaInP.
 7. The method of claim 2 whereinthe transparent conductive layer comprises at least one materialselected from a group consisting of indium tin oxide, cadmium tin oxide,antimony tin oxide, zincoxide, zinc tin oxide, BeAu, GeAu, and Ni/Au. 8.The method of claim 1 wherein the first and second reaction layers eachcomprise at least one material selected from a group consisting of SiNx,Ti, and Cr.
 9. The method of claim 1 wherein the transparent adhesivelayer comprises at least one material selected from a group consistingof Pi, BCB, and PFCB.
 10. The method of claim 1 wherein forming a secondstack comprises forming a second substrate.
 11. The method of claim 10wherein the second substrate comprises at least one material selectedfrom a group consisting of SiC, Al₂O₃, glass materials, quartz, GaP,GaAsP, and AlGaAs.
 12. The method of claim 1 wherein said first reactionlayer and said second reaction layer are held together with thetransparent adhesive layer by chemical bonds.
 13. The method of claim 12wherein the chemical bonds are hydrogen bonds or ionic bonds.
 14. Alight emitting diode comprising: a first stack; a second reaction layerformed on the first stack; a second stack; a first reaction layer formedon the second stack; a transparent adhesive layer formed between thefirst and second reaction layers; and a first electrode and a secondelectrode formed on the first stack.
 15. The light emitting diode ofclaim 14 wherein the first stack comprises: a transparent conductivelayer formed on the second reaction layer, the transparent conductivelayer having a first surface area and a second surface area; a firstcontact layer formed on the first surface area of the transparentconductive layer; a first cladding layer formed on the first contactlayer; an emitting layer formed on the first cladding layer; a secondcladding layer formed on the emitting layer; and a second contact layerformed on the second cladding layer; wherein the first electrode isformed on the second contact layer, and the second electrode is formedon the second surface area of the transparent conductive layer.
 16. Thelight emitting diode of claim 15 wherein the first contact layer and thesecond contact layer each comprise at least one material selected from agroup consisting of GaP, GaAs, GaAsP, InGaP, AlGaInP, and AlGaAs. 17.The light emitting diode of claim 15 wherein the first cladding layer,the emitting layer, and the second cladding layer each comprise AlGaInP.18. The light emitting diode of claim 15 wherein the transparentconductive layer comprises at least one material selected from a groupconsisting of indium tin oxide, cadmium tin oxide, antimony tin oxide,zincoxide, zinc tin oxide, BeAu, GeAu, and Ni/Au.
 19. The light emittingdiode of claim 14 wherein the first and second reaction layers eachcomprise at least one material selected from a group consisting of SiNx,Ti, and Cr.
 20. The light emitting diode of claim 14 wherein thetransparent adhesive layer comprises at least one material selected froma group consisting of Pi, BCB, and PFCB.
 21. The light emitting diode ofclaim 14 wherein the second stack comprises a second substrate, thefirst reaction layer being formed on the second substrate.
 22. The lightemitting diode of claim 21 wherein the second substrate comprises atleast one material selected from a group consisting of SiC, Al₂O₃, glassmaterials, quartz, GaP, GaAsP, and AlGaAs.